Thermxelectric  safety shut-off devices



April 1955 J. H. THORNBERY 2,705,532

RESET AND AUTOMATIC IGNITION MECHANISM FOR THERMOELECTRIC SAFETYSHUT-OFF DEVICES Filed Dec. 15, 1950 2 Sheets-Sheet l 7756/2 f]. Z720 W/haw April 5, 1955 J. H. THORNBERY 2,705,532

RESET AND AUTOMATIC IGNITION MECHANISM FOR THERMOELECTRIC SAFETYSHUT-OFF DEVICES Filed D90. 13, 1950 2 Sheets-Sheet 2 IN VEN TOR.

United States Patent O RESET AND AUTOMATIC IGNITION MECHANISM F%RCIIJPSIERMOELECTRIC SAFETY SHUT-OFF D VI John H. Thornbery, WhitefishBay, Wis., assignor to Milwaukee Gas Specialty Company, Milwaukee, Wis.,a corporation of Wisconsin Application December 13, 1950, Serial No.200,548

Claims. (Cl. 158-128) This invention relates, in general, tothermoelectric control devices, and has particular relation to animproved reset and automatic ignition mechanism for thermoelectricsafety shut-off devices.

While the particular device which will be hereinafter described inconnection with the drawings is a thermoelectric safety shut-off valve,it is to be understood that the present invention is not limited to usewith this particular type of device, but may be employed withthermoelectric safety switches and all similar devices as suitable ordesired.

The present invention may be more particularly characterized as relatingto devices of the character disclosed and claimed in the copendingapplication of Oscar J. Leins, Serial No. 200,615, filed December 13,1950.

According to the invention to which the foregoing application of OscarJ. Leins is directed, there is provided in conjunction with a manuallyoperable finger piece or actuator, an energy storing device in whichenergy is stored by simple manipulation of the actuator, and time delaymechanism which operatively cooperates with the energy storing devicefor providing a time delay between energization of the energystoringdevice and resetting of the armature to attracted position and thecontrolling member to operating position by the energy storing device.

One of the main objects of the present invention is to provide ignitionmeans having a switch operatively cooperating with the operatingconnection between such energy storing device and the valve or othercontrolling member for automatically igniting the pilot burner by theaction of the energy storing device as it operates to reset the armatureto attracted position and the valve or other controlling member tooperating position.

An advantage of the invention resides in the establishment of a flow offuel to the pilot burner and automatic ignition of the pilot burner atcommencement of the action of the energy storing device in its resettingoperation to provide safe lighting should there be any tendency to openthe safety shut-off valve slowly, and theerafter spend some time infully opening such valve.

Another object of the invention is to provide a simple, compact andeffective mechanism which will combine automatic ignition with an energystoring device which may be energized by a simple manual manipulationand without requiring the person operating the device to hold thearmature in attracted position and the controlling member in operatingposition for a prolonged period of time.

Further features and advantages and numerous adaptations of theinvention will be apparent from the following detailed description andthe accompanying drawings.

In the drawings:

Figure l is a sectional view, partially in elevation, of oneillustrative embodiment of the invention, taken along the line 1-1 ofFigure 2, and showing more or less diagrammatically the thermoelectricgenerator and its circuit, the main burner, the pilot burner, and theelectric igniter therefor;

Figure 2 is a fragmentary sectional view, partially in elevation andpartially diagrammatic, taken along the line 2-2 of Figure 1;

Figure 3 is a more or less schematic exploded view showing theprinciples of operation of the device;

Figure 4 is a fragmentary sectional view through the by-pass valvemechanism for the pilot burner;

Figure 5 is an elevational view of the cam guide;

Figure 6 is another elevational view of the cam guide taken at rightangles to Figure 5; and

Figure 7 is an elevational view of the cam shaft showing the position ofthe cam thereon.

Referring now to the drawings, the embodiment of the invention selectedfor illustration comprises a valve body or casing 1 having a fuel inlet2 for receiving suitable gaseous fuel and a fuel outlet 3 for deliveringthe gaseous fuel, for example, to a main burner.

Internally the valve body 1 has a partition 4 provided with a valveopening 5 for placing the inlet chamber 6 in communication with theoutlet chamber 7. An annular valve seat 8 surrounds the inlet side ofthe opening 5.

A hood 9 is clamped to the valve body 1 by a union 9' preferably with ahood gasket therebetween. The interior of the hood 9 may be separatedand sealed from the interior of the inlet chamber 6, for example, by aguide member 10 having an axial opening 11 through which the valve stem10 has reciprocatory movement with packing 12 to prevent leakage of gasalong the valve stem 10' from the inlet chamber 6 to the interior of thehood, as shown in Oscar J. Leins Patent No. 2,126,564, patented August9, 1938. These features per se form no part of the present invention,and therefore are not shown in detail in the drawings of the presentapplication.

An electromagnet 13 is disposed within the hood 9 and comprises, forexample, a U-shaped magnet frame 14 provided about one of its legs witha coil 15. The magnet frame 14 and a terminal bushing 16 may be rigidlysecured to the outer end of the hood 9, for example, by a nut 17', asshown in Harold A. Mantz Patent No. 2,409,947, patented October 22,1946. The lead comprises lead conductors 17 and 18 which, while showndiagrammatically, may be of concentric form as shown in the aboveidentified Oscar J. Leins patent. At one end, the lead conductors 17 and18 are connected in circuit with the coil 15. The opposite ends of thelead conductors 17 and 18 are connected in circuit: with thethermoelectric generator elements 19 and 20 of a thermoelectricgenerator which, while shown in the form of a thermocouple, may be inthe form of a thermopile, or of other suitable form.

The thermoelectric generator elements 19 and 20 are joined at 21 to forma hot thermojunction which may be positioned, for example, to be heatedby the flame of a pilot burner 22 as long as the pilot burner isignited. The pilot burner 22 is disposed, for example, in juxtapositionto a main burner 23 to ignite the same. A fuel supply pipe 24 leads fromthe outlet 3 to the main burner 23 for the delivery of gaseous fuel tothe main burner, for example, through a mixing chamber 25 to which airis admitted, as well understood in the art.

An armature 26 is attached to the outer end of the valve stem 10 withinthe hood 9, and preferably in a manner to permit self-accommodation ofthe armature to the pole ends of the magnet frame 14 when the armatureis in attracted position. A safety shut-off valve member 27 is attachedto the opposite end of the stem 10' within the inlet chamber 6, andpreferably in a manner to permit self-accommodation of the valve member27 to its valve seat 8 when in closed position against the valve seat.

The supply of gas to the pilot burner 23 is under the control of aby-pass valve mechanism shown in detail in Figure 4. This by-pass valvemechanism comprises a bore or opening 28 in the valve body 1. Thisopening 28 is enlarged and internally threaded at one end at 29, and itsopposite end is closed and of reduced diameter at 30. A valve plug 31has an opening 32 extending axially therethrough, and an enlargedexternally threaded end 33 which is screwed into the threaded opening 29preferably with a suitable sealing gasket between the enlarged end 33and a shoulder in the valve body.

A valve stem 34 extends through the axial plug opening 32 with annularclearance or space for the flow of gas therebetween, as will hereinafterappear. A valve member 35 is screwed on the inner end of the stem and isprovided with a yielding valve facing 36 held thereto, for example, by aretainer 37. The valve facing 36 seats against an annular valve seat 38at the inner end of the valve plug 31 when the valve stem 34 is in one 3position, and moves to open position away from the valve seat 38 whenthe valve stem 34 moves inwardly. The opposite end of the valve stem 34is guided for recipgrocatory movement in the reduced diameter opening 0.

Between its ends the valve stem 34 has a valve member 39 integraltherewith or fixed on the stem 34 for reciprocatory movement therewith.The valve member 39 has a yielding valve facing 40 held thereto, forexample, by a retainer 41. The valve facing 40 seats against an annularvalve seat 42 at the adjacent end of the valve plug 31 when the valvestem 34 is in position opposite that in which the valve facing 36 isseated against the valve seat 38. A coiled spring 43, interposed betweenthe valve member 39 and a shoulder 44 in the valve body 1, acts to openvalve member 35 from its valve seat 38 and to close the valve member 39against its valve seat 42. The valve members 35 and 39 are preferably soarranged that the valve member 35 will open before the valve member 39closes, and vice versa, for a purpose which will hereinafter appear.

Between its enlarged end 33 and the valve seat 42, the valve stem 34 hasa pair of spaced annular flanges 46 between which is disposed an annularor O shaped sealing ring 47 of neoprene or other suitable material. Thisring 47 contacts the inner periphery of the bore 28 and forms a gas sealfor preventing the flow of gas from one side of ring 47 to the otherside of the ring externally of the valve plug 31. The valve body 1 has apassage 48 which opens from the inlet 2 or upstream side of the valvebody into the bore or opening 28 on one side of the ring 47. Anotherpassage 49 in the valve body 1 constitutes a pilot fuel outlet, andopens from the bore or opening 28 on the other side of the ring 47 anddelivers fuel to the pilot burner 22 through a fuel supply tube 50leading to the pilot burner. The valve plug 31 has diametrical ports 52which place the opening 32 in communication with the bore 28 on the sideof the seal ring 47 from which leads the passage 49.

For the purpose of cocking or resetting the device, there is provided adrive shaft 54 rotatably supported in a wall of the valve body 1. Theinner end of the shaft 54 extends inwardly into the valve body 1 and isconnected to the coiled spring 55 of a clockwork mechanism designated ingeneral at 56.

The clockwork mechanism 56 is shown only diagrammatically, it beingunderstood that any suitable clockwork mechanism may be employed. Sinceclockwork mechanisms of this sort are well known in the art, suffice itto state that this mechanism has, for example, a suitable escapementsuch as also well known in the art and which, therefore, is shown onlydiagrammatically at 57. In the illustrated embodiment of 'the invention,the clockwork mechanism 56 serves as an energy or power storing device,and the escapement means serves as a time delay means whereby thearmature 26 may be actuated to attracted position and the valve member27 to open position by the energy in the clockwork mechanism after atime delay following energization of the spring 55, as will presentlyappear. The time delay is preferably for a predetermined period of timewhich will permit lighting of the pilot burner 22 and thermoelectricenergization of the electromagnet 13 sufficiently to hold the armature26 in attracted position and the valve member 27 in open position.

The time delay device shown of the spring-type may, for example, be ofthe form illustrated in Marcus H. Rhodes Patent 2,274,635, patentedMarch 3, 1942, or it may be of the form illustrated in Charles B.Simmons Patent 2,258,474, patented October 7, 1941, or of any othersuitable or preferred form. Interval timers of this sort are well knownin the art and therefore a detailed illustration of the same is believedto be unnecessary in the present application.

The outer end of the shaft 54 extends outwardly from the valve body 1and is provided with a knob or finger piece 58 which is adapted to begrasped in the hand of the person operating the device and turned toturn the shaft 54 in a direction to wind or tension the spring 55. Theinner end of the shaft 54 fits telescopically for relative turningmovement in a hollow cam shaft 60 which is rotatably supported in thevalve body 1. The shaft 60 has an integral disc or radial flange 61.Mounted for relative turning movement on the drive shaft 54 and inproximity to the disc 61 is a ratchet wheel 62.

A drive wheel 63 is fixed on the drive shaft 54 for turning movementtherewith. The wheel 63 is disposed in proximity to the ratchet wheel62, and has a pair of diametrically opposite clutch claws 64 struckinwardly therefrom as the device is shown in Figure 2, for cooperationwith a pair of diametrically opposite clutch claws 65 struck outwardlyfrom the ratchet wheel 62. A coiled torque spring 66 is interposedbetween the ratchet wheel 62 and the disc 61, and is connected at itsopposite ends to the ratchet wheel 62 and disc 61, for example, byengagement of its turned ends in openings in the ratchet wheel 62 anddisc 61 as shown in Figure 2. A coiled spring 67 is interposed betweenthe ratchet wheel 62 and disc 61, and acts endwise therebetween.

The cam shaft 60 has in the outer periphery of the disc 61 thereon apair of diametrically opposite detent notches 70 for engagement with ahumped detent portion 71 of a spring 72 for holding the cam shaft 60 inposition. The opposite end of the spring 72 is fixedly anchored at 73,for example, on the valve body 1 within the outlet chamber 7. A camfollower 74 has a forked or bifurcated portion presenting arms 75 whichare slotted at 76 and straddle the cam shaft 60. A cam 68 is fixed onthe cam shaft 60 for rotation therewith, and has a pair of generallydiametrically oppositely directed cam arms 79 which cooperate with thecam follower 74.

The cam follower 74 has an integral pin 80 which telescopes into and hassliding movement in the sleeve portion 81 of a valve disc screw 82. Thevalve disc 27 may, for example, be clamped between the polygonal head ofthe screw 82 and the head of a screw 83 the shank of which passesthrough the valve disc 27 and is screwed into the head of the valve disc82. A coiled spring 84 is interposed between the head of the screw 82and the cam follower 74, and acts endwise therebetween.

To cause ignition of the pilot burner 22 when flow of gas is establishedthereto, an electric igniter is provided. This igniter comprises, ingeneral, a glow coil in the form of a coiled wire or other suitableignition element. Low voltage electric energy for energizing theignition element 100 is supplied, for example, by a stepdown or currentlimiting transformer 101. This transformer 101 comprises a line voltageprimary 102 supplied by line wires 103 connected, for example, to asuitable source of commercial alternating current (not shown) such asmay be adapted for supplying current at a voltage variation from about105 to 115 volts. The secondary of the transformer 101 is indicated at104.

Although the present invention is not limited thereto, the use of atransformer 101, which will supply about 20 to 24 volts for ignitionpurposes, is contemplated. The use of such a transformer permits thelocation of the same at a much greater distance from the appliance thanis possible with a 1 /22 /2 volt transformer. This saves the cost ofrunning a high voltage line to the appliance. Moreover, the cost of theigniter is thereby reduced because the same transformer may be used, forexample, for energizing the igniter and for operating room thermostat orother control devices.

A switch 105 is positioned, for example, adjacent to the ratchet wheel62 and comprises a fixed contact 107 and a movable contact 106. Themovable contact 106 is connected to one side of the secondary 104 by aconductor 108. The fixed contact 107 is connected to one end of theignition coil 100 by a conductor 109. The other end of the ignition coil100 is connected by a conductor 110 to the other side of the secondary104.

For the purpose of closing the switch 105 upon commencement of rotationof the drive wheel 63 under the action of the spring 55 of the clockworkmechanism 56 or other energy storing device, a plunger 111 is interposedbetween the movable contact 106 and the periphery of the drive wheel 63.One end of the plunger 111 has operative cooperation with the contact106, and the other end of the plunger has operative cooperation with theperiphery of the drive wheel 63. When the wheel 63 is positioned asshown in Figure 3, a spring 112 acting, for example, against a flange113 on the plunger 111 forces one end of the plunger into the adjacentnotch 92 in the periphery of the wheel 63. Upon commencement of rotationof the wheel 63 by the energy storing device, the adjacent cam surface94 at the adjacent notch 92 imparts rectilinear movement to the plunger111 in a direction to force the contact 106 into closed position incontact with the contact 107 to close the ignition circuit and energizethe igniter 100.

The operation of the device is as follows:

When the pilot burner 22 is ignited, the heat thereof on the hotjunction 21 of the thermoelectric generator produces a thermoelectriccurrent in the coil 15. The magnet frame 14 and armature 26 arepreferably formed of an alloy of relatively low magnetic reluctance. Asa result, the minute or relatively weak electromotive force produces amagnetic field of suflicient strength so that when the armature 26 isplaced in attracted position the magnetic attraction will hold thearmature 26 in attracted position against the magnet frame 14 and thevalve member 27 in open position. The holding action of the electromagnet 13 at this time is greater than the force exerted by a spring90 which is interposed, for example, between the valve member 27 and theguide member or packing 12, and acts endwise therebetween.

If the flame of the pilot burner 22 is extinguished, the holding actionof the electromagnet 13 ceases to be sufficient to hold the armature 26attracted to the magnet frame and the valve member 27 in open position.As a result, the spring 90 moves the valve member 27 to closed positionagainst its valve seat 8 to shut off the supply of fuel to the mainburner 23 and also the supply of fuel to the pilot burner 22, as willpresently appear. The armature 26 moves to retracted position with themovement of the valve member 27 to closed position.

When it is desired to reset or cock the device, the knob or finger piece58 is grasped and rotated, for example, from the position engaging astop a as shown in dotted lines in Figure 3 into the position engaging astop b as shown in full lines in the same figure. The accompanyingrotation of the drive shaft 54 winds or tensions the spring 55 of theclockwork mechanism 56 to set up and store therein the power or energynecessary for resetting or cocking the armature 26 to attracted positionand the valve member 27 to open position. The rotation of the driveshaft 54 which accompanies rotation of the knob 58 as above described,also turns the drive wheel 63 with the shaft 54 until the clutch claws64 engage with the clutch claws 65 on the ratchet wheel 62 in suchmanner that the ratchet wheel 62 will be turned with the drive wheel 63when the drive wheel 63 rotates in the opposite direction. The clutchclaws 64 and 65 may be of spring or yielding form to permit the claws 64to snap past and engage the claws 65 and to permit disengagement in theopposite direction, or the clutch claws may be of other suitable form topermit the desired action.

It is to be noted at this point that the only manual manipulationrequired to cook or reset the device is to turn the knob 58 to wind ortension the spring 55. The person operating the device may thenimmediately remove his hand. He is not required to hold the armature inattracted position and the valve member in open position until theelectromagnet is energized sufficiently to accomplish this result.

As soon as the knob 58 is released, the spring 55 of the clockworkmechanism drives or turns the shaft 54 in the reverse direction withaccompanying turning movement of the ratchet wheel 62 in the samedirection through the cooperating clutch claws 64 and 65. When the valvemember 27 is closed, the outer end of the valve member 35 engages in oneof a pair of diametrically opposite notches 92 in the periphery of theratchet wheel 62, and, as a result the spring 44 closes the valve 39 andopens the valve 35 of the by-pass valve mechanism for the pilot burner.

At the same time (i. e., when the valve member 27 is closed) the innerend of the plunger 111 engages in the other notch 92 in the periphery ofthe drive wheel 63. As a result, the movable contact 106 is positionedin open circuit position as shown in Figure 3, for example, by itsinherent resilience biased in such direction or under the action of thespring 113 where the plunger 111 is connected to the contact 106, orotherwise as desired. The ignition circuit is thus open, and the igniter100 is deenergized.

Upon commencement of rotation of drive wheel 63 the cam surface 94 atthe adjacent peripheral notch 92 will actuate the valve stem 34 in adirection against the action of the spring 44 and thus move the valve 35to closed position and the valve 39 to open position. Fuel then passesfrom the upstream side of the valve body 1 through passage 48, bore 28,opening 32, ports 52, passage 49, and tube 50 to the pilot burner whichmay be ignited, for example, by the igniter coil as will next appear.

Also at the same time (i. e., upon commencement of rotation of the drivewheel 62 by the clockwork mechanism) the cam surface 94 at the otherperipheral notch 92 will actuate the plunger 111 outwardly and therebyclose the contact 107 into contact with the contact 106. This closes theignition circuit and energizes the igniter 100. As a result, whengaseous fuel issues from the pilot burner ports, it is ignited by theigniter 100. This assures safe lighting because, should there be anytendency for the clockwork mechanism to open the shutoff valve 27 slowlyand thereafter spend some time in fully opening the valve 27, anygaseous fuel which issues from the main burner 23 will be ignited by theflame of the pilot burner 22.

Rotation of the ratchet wheel 62 by the spring 55 of the clockworkmechanism causes tensioning of the torque spring 66. When sutficientenergy is supplied to the spring 66, the spring 72 will be caused toride out of the detent notch 70, and the cam 68 can rotate approximatelyto pop the cam follower 74 up, or it can rotate a lesser amount andthereafter drive the cam follower 74 up more slowly under influence ofcontinuing action of the spring 55 of the clockwork mechanism 56 whichwill further tension the spring 66. These features are contemplated bothways within the scope of the appended claims.

Upward movement of the cam follower 74 causes opening of the shut offvalve 27 and movement of the armature 26 into attracted position againstthe magnet frame of the electromagnet. Assuming that the electromagnet13 has been sufiiciently energized during the time delay by the heat ofthe pilot burner flame on the thermoelectric generator, the armature 26will remain and be held in magnetic engagement as soon as it is actuatedto attracted position, and thus the valve member 27 will be held in openposition. The spring 84 serves as a strain release spring which, whencompressed by the cam 68, has more tension than the spring 90 andprovides for firm engagement of the armature 26 with the magnet frame14. With this structure the adjustment of the parts is preferably suchthat after the armature 26 engages the magnet frame 14 the cam follower74 will preferably still be projected a short distance by the cam 68 toassure good seating of the armature against the magnet frame.

The cocking or resetting rotation of the drive shaft 54 under the actionof the spring 55 of the clockwork mechanism returns the knob 58 to theposition from which it is turned to tension the spring 55. Consequently,upon completion of the resetting operation by the clockwork mechanism,the parts assume their positions for subsequent operation bymanipulation of the knob 58.

If the device is constructed for relatively slow action so that theremight be a tendency to open the shut-off valve 27 slowly, and thereafterspend some time in fully opening this valve, flow interrupter means may,within the broader aspects of the present invention be provided forinterrupting the flow of fuel for the main burner during such interval.

The opening of the valve 35 prior to closing the valve 39 assures that asupply of fuel will be established to the pilot burner 22 from theoutlet chamber 7 before the supply of fuel to the pilot burner from theupstream side of the valve body 1 is shut off by the valve 39. The pilotvalve structure also assures that the valve 39 is opened before thevalve 35 is closed to assure that 'a supply of fuel to the pilot burnerwill be established from the upstream side of the shut-off valve beforethe supply of fuel to the pilot burner from the outlet chamber 7 is shutoff or discontinued.

The valve 27 is closed after being fully open, for example, uponextinguishment of the flame of the pilot burner 22 with accompanyingdeenergization of the electromagnet 13, by the spring 90 as previouslydescribed. While as hereinbefore set forth, the cam 68 is turned through180 by the spring of the clockwork mechanism after it is wound ortightened by turning the knob 58, it will be noted that the cam 68 dueto its form will, upon approximately only 90 rotation, move the armature26 to fully attracted position and the valve 27 to fully open position.If the electromagnet 13 is properly energized, it will hold the armature26 attracted thereto and the valve 27 in-fully open position and thespring of the clockwork mechanism will continue rotation of the cam 68through the remainder of its 180 movement to position 180 from theposition shownin Figures 1 and 3. In this position the spring 84 isreleased or loosened so that the spring 90 will close the valve 27 uponextinguishment of the pilot burner flame.

The embodiment of the invention shown in the drawings is forillustrative purposes only, and it is to be expressly understood thatsaid drawings and the accompanying specification are not to be construedas a definition of the limits or scope of the invention, reference beingbad to the appended claims for that purpose.

I claim:

1. In combination, a first controlling member having an operatingposition and biased to a safety position, an igniter, a secondcontrolling member having a position for energizing said igniter andbiased to a position deenergizing said igniter, holding means forholding said first controlling member in operating position butincapable of actuating said controlling member from safety position tooperating position, an energy storing device effective when energized toactuate said first controlling member to its operating position and saidsecond controlling member to igniter energizing position, said firstcontrolling member being held in its operating position by said holdingmeans, and time delay means between said energy storing device and saidfirst controlling member and providing a time delay after actuation ofsaid second controlling member to igniter energizing position beforesaid first controlling member is actuated to its operating position bysaid energy storing device.

2. In combination, a first controlling member having an operatingposition and biased to a safety position, an

igniter, a second controlling member having a position for energizingsaid igniter and biased to a position deenergizing said igniter, holdingmeans for holdng said first controlling member in operating position butincapable of actuating said controlling member from safety position tooperating position, an energy storing device effective when energized toactuate said first controlling member to its operating position and saidsecond controlling member to igniter energizing position, said firstcontrolling member being held in its operating position by said holdingmeans, and time delay means between said energy storing device and saidfirst controlling member and providing a time delay after actuation ofsaid second controlling member to igniter energizing position beforesaid first controlling member is actuated to its operating position bysaid energy storing device, the bias of said second controlling memberbeing effective to bias said second controlling member to igniterdeenergizing position upon completion of the actuation of said firstcontrolling member to .its operating position by said energy storingdevice.

3. In combination, first and second controlling members each having anoperating position and biased to a safety position, an igniter, a thirdcontrolling member having a position for energizing said igniter andbiased to a position deenergizing said igniter, holding means forholding said first controlling member in operating position butincapable of actuating said controlling member from safety position tooperating position, an energy storing device effective when energized toactuate both of said first and second controlling members to theiroperating positions and said third controlling member to igniterenergizing position, said first controlling member being held in itsoperating position by said holding means, and time delay means betweensaid energy storing device and said first controlling member andproviding a time delay after actuation of said second controlling memberto operating position and said third controlling member to igniterenergizing position before said first controlling member is actuated toits operating position by said energy storing device.

4. In combination, first and second controlling members each having anoperating position and biased to a safety position, an igniter, a thirdcontrolling member having a position for energizing said igniter andbiased to a position deenergizing said igniter, holding means forholding said first controlling member in operating position butincapable of actuating said controlling member from safety position tooperating position, an energy storing device effective when energized toactuate both of said first and second controlling members to theiroperating positions and said third controlling member to igniterenergizing position, said first controlling member being held in itsoperating position by said holding means, and time delay means betweensaid energy storing device and said first controlling member andproviding a time delay after actuation of said second controlling memberto operating position and said third controlling member to igniterenergizing position before said first controlling member is actuated toits operating position by said energy storing device, the bias of atleast said third controlling member being etfective to bias said thirdcontrolling member to igniter deenergizing position upon completion ofactuation of said first controlling member to its operating position bysaid energy storing device.

5. In combination, a first controlling member for fluid fuel burningapparatus having a main burner, an ignition burner and an igniter, sa-idfirst controlling member having an operating position for flow of fuelto said main burner and biased to a safety position shutting oif theflow of fuel to said main burner, a second controlling member having anoperating position for flow of fuel to said ignition burner and aposition in which flow of fuel to said ignition burner is shut off bysaid first controlling member, a third controlling member having aposition for energizing said igniter and biased to a positiondeenergizing said igniter, holding means for holding said firstcontrolling member in operating position but incapable of actuating saidfirst controlling member from safety. position to operating position, anenergy storing device effective when energized to actuate both of saidfirst and second controlling members to their operating and said thirdcontrolling member to igniter positions said first controlling memberbeing energizing position,

.held in its operating position by said holding means, and

time delay means between said energy storing device and said firstcontrolling member and providing a time delay after actuation ofsaidsecond controlling member to operating position and said thirdcontrolling member to igniter energizing position before said firstcontrolling member is actuated to its operating position by said energystoring device.

References Cited in the file of this patent UNITED STATES PATENTS1,807,376 Braden May 26, 1931 2,391,753 Strobel Dec. 25, 1945 2,417,667Strobel Mar. 18, 1947 2,472,384 Ray June 7, 1949 2,475,430 KronmillerJuly 5, 1949 2,484,602 Aubert Oct. 11, 1949 2,506,403 Witzel May 2, 19502,533,982 Weber Dec. 12, 1950 2,578,194 Matthews Dec. 11, 1951

